This invention relates to a control apparatus for stabilizing combustion in an engine.
A device for controlling gas flow in a combustion chamber to improve the combustion characteristic of an engine by providing two independent intake ports in a cylinder, disposing a control valve upstream of each of these ports, the primary port and secondary port, and opening and closing these control valves in accordance with the engine operating conditions, is proposed in JP6-193456A, JP7-197831A, and JP6-213081A, which are Japanese Patent Publications.
In the invention in the first publication, during a partial load operating period or the like, the gas flow in a cylinder is raised by half-opening the primary port and closing the secondary port. However, the directivity of the intake air flow through the intake port is weak, and thus a strong gas flow cannot be obtained inside the combustion chamber.
In the invention in the second publication, fresh air is introduced from the primary port and recirculated exhaust gas is introduced into the closed secondary port, but here also, the directivity of the intake air flow through the intake port is weak and a strong gas flow cannot be generated.
In the invention in the third publication, on the other hand, the interior of the intake port is partitioned by a current plate such that fresh air is introduced from the upper level and recirculated exhaust gas is introduced from the lower level. However, since the primary and secondary intake ports are open at all times, interference with the gas flow in the combustion chamber is likely, and stratification of the recirculated exhaust gas is impossible, and as a result, raising the threshold of exhaust gas circulation proved difficult.
An object of this invention is to provide a combustion control apparatus for an engine which is designed to improve the combustion characteristic by generating a strong gas flow in a combustion chamber corresponding to the engine operating conditions.
In order to achieve above the object this invention provides a control apparatus for an internal combustion engine having an intake valve and an exhaust valve, comprising, at least two independent intake ports, a first and a second intake port, connected to an engine combustion chamber, upper and lower channels which are defined by a partition wall extending along the axial direction of the interior of the first intake port, a first intake control valve provided in the first intake port for opening and closing any one of the channels, a second intake control valve for opening and closing the second intake port on the upstream side of the intake valve, and a controller for controlling the first and second intake control valves in accordance with the operating conditions. The details as well as other features and advantages of the invention are set forth in the remainder of the specification and are shown in the accompanying drawings.